<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        *{
            padding: 0;
            border: 0;
        }
        .container{
            display: flex;
            flex-direction: column;
            border: 1px solid black;
            height: 500px;
        }

        .container div{
            width: 200px;
            height: 50px;
        }

        .item1{
            background-color: red;
            align-self: flex-start;
        }

        .item2{
            background-color: green;
            align-self: center;
        }

        .item3{
            background-color: yellow;
            align-self: flex-end;
        }

    </style>
</head>


<body>
<div class="container">
    　　
    <div class="item1">元素1</div>
    　　
    <div class="item2">元素2</div>
    　　
    <div class="item3">元素3</div>
</div>
</body>
</html>